chore: add WCN 2.0. onboarding docs (#254)

Co-authored-by: Darksome <[email protected]>

Author: nopestack

docs/node-operator-onboarding-legacy.md

@@ -0,0 +1,128 @@
+## WCN Node Operator onboarding 
+
+### Get `wcn_node` binary
+
+Depending on your infrastructure either pull the docker image
+```
+docker pull ghcr.io/walletconnectfoundation/wcn-node:1.451.2
+```
+or build the binary from source
+```
+cargo build -p wcn_node --release
+```
+After a successful build the binary will be located in `target/release` folder.
+
+### Generate cryptographic keypair
+
+```
+cargo run -p wcn key generate
+```
+It will show you the following (**DO NOT use these example values for your node**)
+```
+Key 0
+Private key: pKESPDecF6OB27qj5/JBKNeyBBdLyv8rkw+cgtjlc6E=
+Public key: eMTmrtqEJKIUDvVgRx6igMJrxMJfTx6VE6KFdhsqZKo=
+Peer ID: 12D3KooWHwoETeshEo4sNSLHv1Hoppq7au87kkDyzhQtgvSjacCR
+```
+
+You will need `Private key` in the following configuration section. Store it in a secure place, and make sure you won't lose it.  
+Your `Peer ID` needs to be provided to the WalletConnectFoundation and to be whitelisted in order for your node to be able to join the network.
+`Peer ID` is similar to `Public key` and is a public information which may be freely shared.
+
+### Configure the node
+
+Configuration is being done via environment variables.
+Here's the list of the required ones:
+
+```bash
+# Your private key, previously generated by `wcn key generate`
+export SECRET_KEY=$your_private_key
+
+# Your public IPv4 address, each time your IP changes this variable needs to be updated.
+export SERVER_ADDR=$your_public_ipv4_address
+
+# The name of your organization, ex. "MyOrg".
+export ORGANIZATION=$your_organization_name
+
+# Identifier of the geographic region in which your node is going to be deployed.
+# Available values: eu, us, ap.
+export REGION=$region
+
+# Directory in which the database data is going to be stored.
+# It MUST be persistent.
+export ROCKSDB_DIR=$rocksdb_dir
+
+# Directory in which the consensus data is going to be stored.
+# It MUST be persistent.
+export RAFT_DIR=$raft_dir
+```
+
+The following section depends on the network: Mainnet / Testnet.   
+**Make sure to select the correct network you're connecting to.**
+
+<details>
+  <summary>Mainnet</summary>
+  
+  ```bash
+  # Identifier of the network.
+  export NETWORK_ID=mainnet
+  
+  # For the initial launch of your node (bootstrap) you also need to specify a list of peers to connect to.   
+  export PEER_12D3KooWFJpHSpFCoHqFJsHyc9JA7C9XPTVhyXsiTRucU6TikGWe=<Ask the team for the correct address>
+  export PEER_12D3KooWDdSQWrrkcxs6JGcWYHygwQ4zyoK4SR6Y58f7dsmXsXyp=<Ask the team for the correct address>
+  export PEER_12D3KooWNhADaVPZFcRLxvbfp8abbuPLFz9NGxkh75aHivPHnjyP=<Ask the team for the correct address>
+
+  ```
+</details>
+<details>
+  <summary>Testnet</summary>
+  
+  ```bash
+  # Identifier of the network.
+  export NETWORK_ID=testnet
+
+  # For the initial launch of your node (bootstrap) you also need to specify a list of peers to connect to.   
+  export PEER_12D3KooWDBZx6LibN1Lxvtb45yFNBfons96bn79AokA2amcJpcZd=<Ask the team for the correct address>
+  export PEER_12D3KooWDfseE1zdkdPjhwHYfdSUSRZ5mGJoUTNUbiyehWrMDhDM=<Ask the team for the correct address>
+  export PEER_12D3KooWJTtT7wUsqWtcGufQrYCcPm8s5vHib9cCVZWiVUKMJz5a=<Ask the team for the correct address>
+  ```
+</details>
+
+Optional configuration variables you may also be interested in:
+```bash
+# Port of the Raft API server.
+export RAFT_SERVER_PORT=3010
+
+# Port of the Raft API server.
+export REPLICA_API_SERVER_PORT=3011
+
+# Port of the Coordinator API server.
+export COORDINATOR_API_SERVER_PORT=3012
+
+# Port of the Admin API server.
+export ADMIN_API_SERVER_PORT=3013
+
+# Port of the Prometheus metrics server.
+export METRICS_SERVER_PORT=3014
+
+# Port of the Migration API server.
+export MIGRATION_API_SERVER_PORT=3015
+```
+
+### Prepare your infrastructure
+
+#### Firewall
+
+`Raft API`, `Replica API` and `Migration API` server ports need to be open for all connections in your firewall settings.  
+Default ports are `3010`, `3011` and `3015`, however you can change them as described in the previous section.
+
+#### Graceful shutdown
+
+WCN nodes require large graceful shutdown timeout to be configured, depending on the network condition the node may refuse to shutdown after `SIGINT`/`SIGTERM` for quite some time.  
+Node orchestration is being managed internally by the network itself, if there's an ongoing data migration your node may be forbidden from shutting down. Also, there's a limit on how many nodes can be offline at the same time.   
+
+This is required to achieve high availability.
+
+So, you need to make sure that your infrastructure won't `SIGKILL` the WCN node prematurely.  
+WalletConnectFoundation nodes are configured to have `12h` graceful shutdown timeout. But we expect other operator nodes to have at least `1h` of graceful shutdown window.
+